Otto Pérez Molina is Guatemala's President, no longer. After months of marching in the streets  demanding justice and accountability, Guatemalans receive today many welcomed news. The president has resigned and will be jailed until an evidentiary hearing about the massive bribery operation  called La Linea (“The Line”) which also led to the resignation o f former Vice President Roxana Baldetti.
— AJE News (@AJENews) September 3, 2015 
On Wednesday, September 2, a judge issued an arrest warrant for Guatemalan President Otto Pérez Molina, who was stripped of his executive immunity after an unanimous congressional vote on September 1—a first in Guatemalan history and the first Central America head of state to be impeached. He is accused of illicit association, bribery, and customs fraud.
— Xeni Jardin (@xeni) September 3, 2015 
Until the last moment, Pérez Molina insisted that he would not resign. Overnight, however, he changed his mind.
— nómada (@nomadagt) September 3, 2015 
Remember, OPM [Otto Pérez Molina] is still the President, until he is placed in pretrial custody or the Congress accepts his resignation.
Today, the Congress accepted his resignation and, according to the Guatemalan Constitution, the current Vice President, Alejandro Maldonado, will be sworn  in for the remainder of Pérez Molina’s term, which ends in January, and a new vice president will be appointed by the Congress, from a list submitted by President Maldonado. She or he will serve until January 14, 2016.
Trained by the US Military Academy, the School of the Americas , and appointed as the delegate of the Army to negotiate the Peace Accords, Pérez Molina completely lost the support of the US Government and the international community, after revelations that his government was involved in a variety of dubious business deals.
Online, human rights activists like Phil Neff responded to Pérez Molina's resignation with admiration for Guatemalans:
Guatemala: from convicting a former dictator for genocide to arresting a sitting President. #respect 
— Phil Neff (Version) (@cascadiasolid) September 3, 2015 
General elections will take place in Guatemala in less than 72 hours and the announcement of Pérez Molina's arrest will clearly be an important factor. Since the UN-backed International Commission Against Impunity  released a report indicating that a large amount of Guatemalan campaign funding comes from illegal sources and criminal networks, citizens—naturally concerned—have called on electoral authority to suspend the elections and conduct a comprehensive audit of all candidates.
After resigning from his post and having the resignation accepted by Congress, Pérez Molina presented himself before the courts for the evidentiary hearing. There, the judge ordered  the former president to be held in prison.